1. Field of the Invention
This invention generally relates to a total hip replacement and, more particularly, to a method of and device for providing a barrier at a predetermined depth in a cavity formed in a cut femoral shaft for improving the connection of the femoral prosthesis in the cavity of the femoral shaft.
2. Description of the Prior Art
The concept of implanting a femoral prosthesis in a cut femur by a self-curing cement, of course, is well known in the art. However, only when there is no gap between the prosthesis and the bone can it function effectively in transferring and spreading the weight-bearing forces from the prosthesis to the bony structures of the femur without the loosening or wobbling that ultimately is blamed for the pain and failure encountered in a prosthesis.
In the past, a femoral prosthesis has been attached to a cut femur by self-curing acrylic cements, which have been kneaded to a putty-like consistency and introduced into the cavity prepared in the femur, herein the prosthesis is driven into the cement-filled cavity with a slow steady pressure. This method of cementing a femoral prosthesis to the femur shaft has not been entirely satisfactory in that the intramedullary canal of the femur shaft is relatively hollow, particularly in the more distal portions of the shaft and consequently gaps frequently occur in the cement between the prosthesis and the bony structure of the femur thus not spreading the weight transfer evenly therebetween.
Attempts have been made in the past to employ a cement in the liquid state in the repair of the femur for overcoming the aforementioned problem in this case, a barrier or plug must be created in the intramedullary canal to prevent the liquid cement from being forced distally into the relatively hollow canal. Attempts have been made to provide a barrier at the bottom of the cavity opening into the canal by introducing a small amount of cement at the distal most point that the prosthesis will be inserted into the cavity and allowing it to harden. Although this technique is generally effective, it does have some complications in that, at times, the cement plug, prior to hardening, migrates proximally in the cavity, thus preventing full insertion of the prosthesis. This condition requires removal of the hardened cement plug and not only is the removal thereof a technically difficult task, but the hardening and drying time of the cement is about 15 to 20 minutes which is extremely time consuming in a surgical procedure.
Also attempts have been made in the past to employ plugs made from bone to form a barrier in the intramedullary canal. Although bone plugs work well if properly placed, exact placement thereof in the canal is difficult and inconsistent as they are conventionally inserted in the canal with a hemostat. For example, if a bone plug is not inserted far enough down the canal, the prosthesis will be forced into a malposition resulting in an inadequate placement of the prosthesis.